This invention relates to the use of certain proteins to improve healthy growth and reduce the risk of development of insulin resistance as a consequence of uncontrolled (unhealthy) catch-up growth in infants and children and weight recovery in adults.
It has been recognized for many years that the growth pattern of young mammals who suffer stress whether as a result of physical illness or injury or psychological trauma is often interrupted. If the young mammal makes a swift recovery and adequate nutrition is available, it may then compensate for the growth which should have taken place during the period of stress and this sudden spurt of growth is known as “catch up growth”. However, this does not always happen. For example, the young mammal may suffer from anorexia both during the illness or trauma and in its immediate aftermath and food intake may therefore be limited. In severe cases it may be that the animal never attains the physical stature that it would have reached had the stress not been suffered.
This phenomenon may be seen in young mammals including humans from infancy throughout the period in their lives during which they are still growing. It may be particularly noticeable in the case of young mammals born prematurely as well as those which do not achieve normal growth patterns before birth for whatever reason. In the case of human infants such individuals may be described as subject to intra-uterine growth restriction (“IUGR”).
Although it is desirable to ensure that reduced growth during periods of physical or mental stress is compensated, it is also important to reduce the risk of later development of metabolic disease as a consequence of unhealthy catch up growth. Without being bound by the theory, it is also believed that catch up growth should not be excessive as there are indications that periods of very rapid and/or very extensive catch up growth particularly during infancy may be linked with a risk of future obesity. It is also important that catch up growth is not accompanied by excessive fat deposition and hyperinsulinemia, as these features of catch-up growth may be linked with a risk of future obesity and diabetes.
Indeed, there is increasing evidence to suggest that people who had low birth weight or who were stunted during infancy or childhood, but who subsequently showed catch-up growth, have higher susceptibility for central obesity, type 2 diabetes and cardiovascular diseases later in life (Cianfarani S, Germani D, Branca F: Low birth weight and adult insulin resistance: the ‘catch-up growth’ hypothesis. Arch Dis Child Fetal Neonatal Ed 81:F71-3 (1999), Levy-Marchal C, Jaquet D, Czernichow P: Long-term metabolic consequences of being born small for gestational age. Semin Neonatol 9:67-74 (2002)). Recently, it has been suggested that the phase of catch-up growth may correspond to a state of hyperinsulinaemia concomitant to a disproportionately faster rate of recovering body fat than that of lean tissue (Dulloo A G. Regulation of fat storage via suppressed thermogenesis: a thrifty phenotype that predisposes individuals with catch-up growth to insulin resistance and obesity. Hormone Research 65, Suppl 3: 90-7 (2006)).
Insulin resistance occurs when the body fails to respond properly to the action of insulin produced by the pancreas. It occurs most frequently in adults, but is being noted increasingly in adolescents and younger children as well. The body attempts to overcome this resistance by secreting more insulin from the pancreas. The development of Type 2, or non-insulin dependent, diabetes occurs when the pancreas fails to sustain this increased insulin secretion.
This dispropostional rate of recovery of body fat relative to lean mass also occurs in adult during phase of “weight recovery” following weight lost due to illness, dieting, etc.
There is, therefore, clearly a need for an intervention specifically designed to address the nutritional needs of infants and young children undergoing periods of catch-up growth whilst reducing their risk of developing insulin resistance or Type 2 diabetes or obesity later in life.
Similarly there is a need for interventions specifically designed to address the nutritional needs of subject, of young age or adults, undergoing weight recovery whilst reducing their risk of developing insulin resistance or Type 2 diabetes or obesity later in life.